The Chinese superstar avoided an upset by progressing 6-2 6-2, as she did in round one, to set up a potential repeat of last year's third-round match against Laura Robson, who shocked her last year.
Read how Li made it through to round three below.
4.01pmAfternoon folks! It's already day three at Flushing Meadows and first up on the main Arthur Ashe showcourt we have women's fifth seed Li Na up against 29-year-old Swede Sofia Arvidsson.
4.04pmWe're still waiting for the players to appear on Ashe so while we wait let's look at how they made it here...
4.07pmArvidsson's US Open did not begin well when she lost the first set 6-1 against Petra Cetkovska but rallied to take the next two 6-4 6-1.
4.09pmLi came up against Belarus's Olga Govortsova and made light work of her match, coming through 6-2 6-2 on Monday.
4.13pmH2H: The pair have met twice in the past and Li won both, with the last meeting at the Aussie Open in 2011.
4.15pmAs mentioned above, the winner of this match is likely to face 30th seed and British number one Laura Robson in round three. That's if the teenager beats Caroline Garcia as expected today.
4.17pmThe pair have now completed their warm-ups and we're ready to go on Arthur Ashe. The chair umpire today is Leanne White from Australia.
4.18pmIt's Li to serve first and she loses the opening point by hitting long with a backhand.
4.20pmArvidsson moves ahead at 0-30 but is now 40-30 down.
4.23pmLi tries a serve-and-volley on game point but the serve wasn't wide enough and Arvidsson swipes a forehand winner down the line. Back to deuce.
Arvidsson *0-1 LiLi comes through a tough opening game as Arvidsson mistimes a groundstroke at advantage.
4.26pmLi has started very aggressively on the return and just opened up TWO BREAK POINTS with a sumptuous cross-court forehand pass on the run.
Arvidsson 0-2* LiBREAK! She takes the first with a deep return that Arvidsson simply can't react to in time.
Arvidsson *0-3 LiA much more confident hold of serve this time from Li as she holds to 15. Both women are hitting it pretty hard at the moment, with Li's greater accuracy and placement the reason for her lead.
Arvidsson 1-3* LiArvidsson gets on the board for the first time by coming through a game that went to deuce. There was a couple of nice groundstrokes from the Swede there so she can take encouragement from that.
Arvidsson *1-4 LiNo danger of a break back from Arvidsson at the moment though as Li holds to love. In the final point there Arvidsson was battering the fifth seed's backhand but couldn't wear it down before hitting long with a forehand. Resilient stuff from Li.
Arvidsson 2-4* LiA comfortable hold for Arvidsson but all that will be remembered from that game was Li's quite incredible drive-volley. Arguably she should have let the ball bounce but just decided to take it on and crashed it away for a winner.
Arvidsson *2-5 LiA second ACE of the match for Li closes out another game as we approach half an hour of play on the game clock. Arvidsson must now win three games on the trot to not lose the first set. I can't see it happening.
Arvidsson 2-6 0-0* LiSET! Oh dear, Sofia! The Swede has game point at 40-30 but then proceeds to double fault twice to gift Li set point. The Chinese converts as she hits deep with a backhand and Arvidsson can only reply long. Just 32 minutes that set took.
4.53pmLooking at the stats from that opening set, the standout one is the winner count where Li has 13 and Arvidsson just two. The Swede has also made more errors with 13 to Li's nine.
Arvidsson 2-6 *0-1 LiAn assuring start to the second set from Li as she comes through her opening service game.
4.57pmThe Chinese now has THREE BREAK POINTS to open up an early advantage in the second.
Arvidsson 2-6 0-2* LiBREAK! She takes it on the second by walloping a forehand into the corner, with Arvidsson only able to watch the ball whizz past her.
5pmArvidsson has TWO BREAK-BACK POINTS as Li fires wildly long with a backhand...
Arvidsson 2-6 *1-2 LiAnd break back she does! Li saved the first with a fine backhand down the line but then goes for the same shot on the next point and dumps it into the net.
Arvidsson 2-6 2-2* LiArvidsson is able to consolidate the break back and level up the second set thanks to some booming backhands.
Arvidsson 2-6 *2-3 LiShe can't then trouble the Li serve again though as the Chinese holds to 15.
Arvidsson 2-6 2-4* LiAt 40-15 I was going to write that it had not been as Li-thal from Na in this set but then she slapped away four points in a row to re-establish the break and move within two games of the match.
Arvidsson 2-6 *2-5 LiAnd now just one as she races through that game. The Chinese has 29 winners to Arvidsson's four.
5.22pmNo sign of an Arvidsson comeback as she hits into the net to give Li TWO MATCH POINTS...
Arvidsson 2-6 2-6 LiGAME, SET AND MATCH LI NA!
5.23pmShe misfires on the first but takes the second to book her place in round three.
5.25pmThere's a sense of deja vu about that victory as it was the same scoreline as the first round - 6-2 6-2 while both sets today lasted exactly 32 minutes.
5.28pmNext up for Li Na is likely to be Laura Robson and there's more to that potential match than meets the eye because Robson stunned Li last year in the third round of the same tournament.
5.31pmRobson is due to play the second match on Court 11 and she could be up very soon as Marcos Baghdatis is two sets and a break up against Go Soeda at the moment over there.
5.34pmThanks for joining SM for coverage of this one. Be sure to stick around on site for more commentaries, reports and reaction from Flushing Meadows.